Black River,
Sadly, Coffin Maker, RoyceP and the others are right, not because that is the "way it was always done" but because it is not safe. So let's shed some light on this:

I think something that is being overlooked in this “discussion” is the difference between Large Rifle and Large Pistol Primers.

When discussing the .30 WCF cartridge, remember it uses Large Rifle primers that have a cup thickness of .027”.  The Large Pistol primers “all” have a cup thickness of .020”.  That thickness is 26% thinner than the rifle primers (plus some pistol primers are softer than others, I can attest to that).

These are the facts:

• We are talking about Round Nose Bullets  in .30 WCF.  We are not talking about spire points of any kind or plastic “Ballistic Tip” type of bullets.
• A rounded nose bullet in the .30 WCF rests against a relatively thick primer cup, so  we would expect less of a problem with that and with other Large Rifle Primer cartridges that are chambered in tubular magazine rifles.
• NONE of us shoot centerfire Rifle cartridges in standard Cowboy matches, we shoot “pistol catridges” in carbines and rifles.  This means we have to use Pistol Primers in any cartridge using a Large Primer (Large Rifle primers are too tall, the primer pocket in a rifle case is .007-.008” deeper.) You cannot use Large Rifle Primers in “Pistol Cartridges”) Therefore we have thinner primer cups for a less than flat nose bullet to push against.
• Don’t get this confused with Small Pistol and Small Rifle Primers, because YES, you can use Small Rifle Primers in Pistol Brass.  We used Small Rifle Primers in .38 Super, .38 Super Comp and 9x23 loads (back when Men were Men and we had a 175 Major Power Factor).  But, we could because the primer pocket depth is the same for Small Rifle and Small Pistol pockets. 
• Just so you know, Small Pistol Primers (including magnum) have an even thinner Primer cup, .017”.  So we used either standard Small Rifle Primers with .020” thick Primers and some pistols could set off the Magnum Small Rifle Primers (includes the CCI 41 for Mil-Spec ammo) with .025” thick cups.  All Small Magnum Rifle Primers have thicker cups.
• The worst case scenario for bullets hitting primers in a tubular magazine is someone dropping a magazine follower on a partially loaded 1860 Henry (Modern Centerfire reproduction) with less than flat nose bullets.  There have definitely been some magazine tube explosions. 

Winchester has not and never will advocate, recommend or allude to using a round nose bullet in a tubular magazine for a “pistol caliber” weapon.  I know the .30-30 well, I have four Model ‘94s in .30-30 (mine was made in the ‘50s but the others are prewar)  All have used Remington, Winchester and UMC ammunition over the years, both flat point and everything else, silver tips, power points, core-lokt, Lubaloy, you name it.  Entire family shot them, I have them all now and never heard tale of anyone even every hearing about a magazine tube exploding. I also never heard of trouble with ‘73s and ‘92s we had.  All of the ammo I inherited for these pistol caliber rifles and carbines had flat nose bullets.  Was that chance?  I think not, it's what was sold for them.

Even with all of my family experience with .30 WCF using in many cases round nose bullets you will never see me use, advocate or even hint that you can use less than a flat nose bullet in a pistol caliber tubular magazine carbine/rifle.

So as Coffin Maker and RoyceP and all of the others counsel, why take a chance with a pistol caliber tubular magazine carbine/rifle?  It’s not like there is a dearth of flat nose bullets out there for them.  And please don't add to the confusion (that's my job...)

~Mako

I guess if you want to be stupid and reload ammo that is unsafe we can't talk you out of it. Go ahead, do whatever.

Does anybody know what the throats would be on a .45 ACP cylinder?

The reason I ask is because my 3rd Gen Colt's regular .45 Colt cylinder has .455 - .456" diameter throats.  If the .45 ACP has .451 - .452" throats I bet the Cowboy Special could be a tack driver.

B.R.S. 

I'm sorry, but some of your "Devils Advocate" argumentative bent is . . . . dumb.  You as WHY did Winchester do things sufficiently in the past, there is no one still living who could authoritatively answer that question.

You also ask "So What is True and what is Myth.  Have you really chosen to ignore the FACT there have been Magazine Detonations??  Do you really choose to ignore there CAN be Magazine detonations??

Or are you just determined to play the part of a TROLL??

First off I do like discussing with you and I agree with you on most topics.   But I am not dumb.  I have been tested many times.  My comments are not dumb people just do not look at all aspects of the WHYS.

Next you did not completely read both of my postings. My line 6 in the last posting --- "And Yes, I have read where people have had Detonations but never have seen full investigation or reports as to the WHYS.  So many other possibilities with reloading.  Yes to me, Flat Nose Bullets are the Safest Option and should be the Default for people that do not understand design shapes and terms."  My comment is those that just jump to flat bullet shape 'or' you will have 'detonation', are just using the Safety 1st mentality and not looking for the real reasons.  My comment about the original Winchester 1894 design bullet is proof of this.  The Sear catalog 1897 & 1902 list a full round nose Metal Patch bullet as the 30WCF only cartridge.

My Asking for comments about old and newer bullets, lay out as this --- Winchester flat nose 1860 to 1895 = 35 years +.  Then the 1894 to 1956 = 62 years -- only Full Radius Round nose design in the 30WCF (Win & Ideal/Lyman molds).

You know that during that 62yr there where a lot of gun writers and catalog articles, being done.  Don't use the No Info exists.  My point, how many detonations were written about during that 62 years that we have suddenly gone to -- ABSOLUTE FLAT NEEDED.

Was it just a hunting change and not a detonation issue in tubular magazines, all the time?

Thanks

Yes mold is stamped Snakebite 158 grains